Lead control for diesel engines



Aug. 9, 1932. R. HILDEBRAND LEAD CONTROL FOR DIESEL ENGINES Filed Nov. :5, 1950 2 Sheets-Sheet 1 g- 9, 1932- R. HILDEBRAND 1,871,268

LEAD CONTROL FOR DIESEL ENGINES Filed No v. 3. 1950 2. Sheets-Sheet 2 197' To IPA/5K5,

Patented Aug. 9, 1932 omre 7 Lean Conrad: non mesa: airtime" a ease filed N venter a, 1930". S rial no: 49293 This invention relates to devices" of the kind connnonly-referred to as lead controls that are used on-Diesel engines to change the relationship between a driving member on a 5 driving shaft of the engine, and a driven member on the cain shaft of the fuel injectionp'ump in order to vary'the period the cycle of operations of the engine at which fuel is sprayed or injected into the cylinders,

10 the ternrlead angle being generally understood to niean the angle of the crankshaft before it reaches its upper dead center at the moment the fuel spray begins;

The main object of my invention is to provide a lead control tor Diesel engines, which is of such des'ignthat the lead of the engine can be changed while the engine-is in operation, thereby over-coining an inherent objectionable characteristic of lead controls '20 of conventional design which necessitates stopp 'g the engine each time the lead of the eiigineis changed. 7

Another object is to provide an ineXpen5 si-ve lead control of the t pe mentioned, that i is of rugged construction and of such design thatthe' operator in chargeof the'engine can easily adjust the lead to suit the load, and moreover,- is' supplied with a visual gauge or indicator which shows whether the lead is near its maximum or minimum. Other 0bj-ects and desirable features of my invention will be hereinafter pointed out.

Figure 1 of the drawings is' a front elevational view of a lead control for Diesel engines constructed in accordance with my invention. Figure '2 is a detail sectional view, taken on the- 11m 2- 2 of Figure 1". Figure 3 is a verticaltransverse sectional view of the housing that encase'sthe chain' example, as sproeket, attached to the crank 1 shaft of the engine, B designates a driven menibensuch as a sprockenatta-ched to the cain shaft of the fuel inj ectionp uinp and designates a flegibie' endless member; such as" a chain that co-ofperates} with said sprool'e etsto I drive the fuel puinp from the crank shaft olitheiengine. Ihe'purnp driving hain C held operative relationship with the teeth of the sprocketswith which it n-op ineansof two idler sp'ro'ckets D and D arran gedat op'p'ositesidesof said chain; as shown in Figure 3, so as to take upthe slack in the chain between the driving sprocket A andthe driven sprocket B. "The idleis and D are mounted so thaththe'y can be. shifted bodily either to the right or to the left, looking at Figure 8, so as to cause the sprocketB to rotate slightly relatively to the driving-sprocket A, thereby changing the relationship between the drivenm'e inber on the pump andthe driving niernben o'n'th'e crank shatt of the engine, and thus'varying the 'period in the'cycle 'of operations'of the engine at which fuel is sprayed into the cylinders. Diesel engines of conventional ole signare equipped with parts of the general character and' arrangement above describedg but in conventionalfdesignsthe tak e u'p idlers D and'Dare'so' constructed and arranged that it is necessary to stop-the engine preparator'y to: moving of shifting said'idlersito ef fect aehange in the" lead; of the engine. Usually, the take-up ,i'dler's are mounted on carriers that areYcapable of being adjusted when-the engineis stoiaped; biit'said carriers are normally held statidnary oi atrest'.

As previously stated, the nia-inobject of m invention'is to 'ov'efcome thenec essity of stopping a'Die s el engine'whenever the lead of the 5 0 engine isto be changed, and provide a'simple means by which t'heope'rator, in charge of the engine may quickly change the lead'to suit the'leaawhne the engine continuesin' operation; To this end; I have deviseda lead @011 trol',-which, briefly described, comprises a spring weight,orother yieldable force'lfdr causing 'jthertake-np' idler at the slack side of the-flexible pumpdriving element C to. exert pressure on" said element in a direction tending to hold said element taut, and a shiftable stop or abutment capable of being ad-' of the flexible pump driving element, and a spring or equivalent means is used to yieldingly hold the other take-up idler in engagement with the slack side of the pump driving element, but in an engine whose crank shaft is adapted to rotate either in clockwise or in anti-clockwise direction, it is necessary to provide an adjustable stop or abutment for each of the take-up idlers and also combine a spring or equivalent means with each of the take-up idlers so as to effect the necessary reversal in the bodily movement of the take-up idlers when the direction of rotation of the crank shaft of the engine is changed. v i p I have herein illustrated my invention embodied in a lead control for a reversible Diesel engine, but I wish it to be understood that theinvention is applicable to an engine whose crank shaft is intended to rotate in only one direction and also that various changes may be made in the design, construction and -arrangement of the co-acting parts of the apparatus without departing from, the spirit of my invention. As shown in Figure 3, the idlers D and D are mounted on shiftable carriers 1 and 1?, preferably rockable carriers, arranged at opposite sides of the pump driving chain D and rigidly attached to horizontally disposed rock shafts 2 and 2 that proj ect forwardly through the front wall of the housing that encases the mechanism used to transmit movement fromthe drive shaft of the engine to the cam shaft of the fuel injection pump. 'The arms3 and 3* that are rigidly attached tothe front ends of the rock shafts 2 and 2 respectively, co-operate with a control mechanism or adjusting mechanism which comprises springs 4 and 4 for moving the idler carriers 1 and l inwardly towards each other, stops or abutments 5 and 5 for controllingthe position of the takeup idlers that act on the tight side of the chain 0, and a manually-operated adjusting shaft 6 for shifting or changing the position of the stops 5 and 5?. Various means may be I used for moving or shifting theadjusting shaft 6, the means herein illustrated for this purpose consisting of a hand wheel 7 rotatably mounted on astationary bearing 8 and provided with a nut or internally-threaded bushing 9 that receives an externally screwthreaded spindle 10 on a cross head 11 which is reciprocatingly mounted in the bearing 8. Said cross head is held against rotarymovement by laterally-projecting pins 12 thereon that enter elongated slots 13 in the bearing 8, and the adjusting rod 6, previously referred to, is connected by links 14 or in any other suitable manner to the cross head 11, so as to cause the adjusting rod 6 to move endwise when the hand wheel 7 is rotated. Pins or bearings 15,:Which are rockably' mounted in the upper end portions of the arms 3 and 3 are provided with holes through which the adjusting rod 6 passes freely, and the stops or abutment members 5 and 5?, previously referred to, are mounted on the rod 6 in such a position that the stop 5 is arranged on the outside of the arm 3 and the stop 5 is arranged on the outside of the arm 3 The springs 4 and 4 previously referred to, are contractile springs and are attached at their outer ends to the arms 3 and 3, respectively, and attached at their inner ends to a bearing 16, rigidly mounted on the adjusting rod 6. In order that the operator in charge of the engine may easily ascertain Whether thelead is near its maxi mum or minimum, the cross head 11, previ; ously referred to, is provided with a pointer, designated by the reference character 17 in Figure 1, that co-acts with a dial 18 carried by the bearing 8 in which the cross head reciprocates, and provided at its opposite ends with the words Minimuma11d Maximum.

When, the crank shaft of the engine is rotating in clockwise direction the tight side of the chain C, i. c., the right hand side, will tend to move the right hand idler D outwardly, or to the right,looking at Figure 3,

thereby causing the arm 8 that is attached to the carrier 1 of said idler to press tightly against the stop or abutment 5 on the adjusting rod 6. At such timesthe spring P that is associated .with the left hand idler D, which acts on the slack side of the chain C, exerts an inward pull on the arm 3*, with the result that the left hand idler D will exert pressure on the chain C in a direction to take up the slack in saidichain and hold it in oper: ative relationship with the driving sprocket A and the driven sprocket D. By moving the stop 5 to the right or to the left, the right hand idler D will be shifted bodily, thereby effecting a change in the relationship between the driving sprocket and the driven sprocket,

and thus causing thelead of the engine to be changed. So long as the engine continues to rotate in clockwise direction the stop 5 associated with the idler D that acts on the slack side of the chain 0 will remain inactive, and. said left hand idler will be held yieldingly in engagement with the chain by the pressure which the spring 4* exerts on the carrier of, said idler. When the engine. is reversed or,

caused to rotate in anti-clockwise direction, the left hand side of the chain C becomes tight and the right hand side slack, with the result that the chain exerts pressure on the idler D in a direction tending to move it outwardly, or to the left, looking at Figure 3, whereupon the stop or abutment 5*" will come into action torestrict or resist the outward movement of the idler D. The stop 5 is now in an inactive condition or out of engagement with the bearing in the upper end portion of the arm 8 through which the adjusting rod 6 passes, and so long as the engine continues to rotate in anti-clockwise direction, the stop 5 will remain inactive and the spring 4 that is associated with the right hand idler will cause said idler to act on the slack side of the chain C and take up the slack in the chain. No matter in what direction the crank shaft of the engine turns, it will be seen that the idler on the slack side of the chain C will be held against the chain by the pressure of the spring that is associated with the carrier on which said idler is mounted. Hence, the force exerted by this idler is yielding and self-adjusting. Conditions are different on the tight side of the chain, as this idler is held in position not only by its spring, but also rigidly by the co-action of the carrier of said idler with the stop on the adjusting rod 6. Assuming that the crank shaft of the engine is rotating in clockwise direction, the right hand side of the chain C tends to straighten out, but is prevented from straightening out fully by the spring 4 and the stop 5 that limits the outward movement of the carrier 3. By turning the hand wheel 7 in one direction or the other the lead angle can be accurately increased or decreased, with the result that the operator in charge of the engine can accurately adjust the lead to suit the load. Regardless of whether the lead is increased or decreased, the take-up idler that acts on the slack side of the chain C will always hold said chain steady, due to the fact that said idler is under the influence of a spring or similar means which holds it yieldingly in engagement with the chain.

Owing to the fact that the above described adjustments or changes in the position of the carriers for the take-up idlers may be made while the engine is in operation, the injection of the fuel into the cylinders of the engine can be accurately controlled to secure eflicient operation of the engine. Such a lead control is inexpensive to manufacture; it is of sufliciently rugged design to insure its standing up successfully while in use, and in addition to being easy to adjust, enables the operator in charge of the engine to easily determine whether the lead is near its maximum or minimum.

In some instances the idler on the slack side of the chain has a tendency to flutter While the engine is in operation, due to the fact thatsaid-idler is not" held rigidly inplace, and the force transmitted by the chain is continuousl -y varied. If-dejsired, my improved lead control can'be provided with. ameansfor overcomingthis, which means-may consist of nut 19-- mounted onthe adj ustmg shaft 6, as v shown in Figure 1, and adapted-to be screwed against the arm 3% after the l eadrhas been-adjusted to: best suit theload and speed oftheengine.-v v r Having; thus described my invention, what Icla'i-m as new and desire to secure byLettersPatent is j Y a lead control forDiesel engines, the combination of a flexible driving; element for transmitting movement from-a drivingshaftof the engineto the fuel injectionpump, shiftahle idlers that act on; opposite sides of said flexible element means tor-holding the/idler at the slack sideofthe' element in yielding-engagement with the same, and a means capable, of being adjusted while the engine isin operation. for bodily shifting the idler at theti-g'ht side of said flexible element tochange. the leadof the engine .2. In a Diesel en'gine,the combination of? adriving member operated by a driving shaft of the engine, a. driven member associated with a fuel injection pump, an endless fiexible element for transmitting movement from said driving. member to said driven: member, idlers. at opposite sides of said flexible element for taking up the slackin same, an:

adjiistable stop for controllingthe position of the idler'that acts on the tight side of said flexible. element, andmeans for holdingthe otherlidler in yielding engagement with the slack side of said flexible element.

3. In a Diesel engine, the combination of a sprocket; operated by a driving shaft of the engine, a driven sprocket associated with the fuel injection pump, an endless sprocket chain that travels over said sprockets, take-up idlers at opposite sides of said chain, bodily shifting carriers for said idlers, means associated with said carriers for causing said idlers to exert pressure on said chain in a direction tending to take up the slack in same, and shiftable stops under control of the operator in charge of the engine capable of being moved while the engine continues in operation for varying the position of the carrier of the idler that acts on the tight side of the chain.

4. In aDiesel engine, the combination of a gine for limiting the outward movement of either of said idlers, produced by the outward force or thrust which the tight side of the chain exerts on the idlerthat acts on same.

I 5. In a Diesel engine, thecombination of a driving sprocket connected to a driving shaft of the engine, a driven sprocket connected to the cam shaft of the pump, an endless chain that travels over said sprockets, take-up idlers arranged at the opposite sides of said chain, rockable carriers for said idlers, springs associated with said carriers and arranged so as to exert pressure on'the idlers in a direction tending to move them inwardly towards each other, and a manually-operated adjusting rod provided with stops or abut ments. arranged so as to restrict or limit the outward movement of the take-up idlerthat acts on the tight side of the chain.

6. In a Diesel engine, the combination of a driving sprocket attached to a driving shaft of the engine, a driven sprocket combined with the fuel injection pump, an endless chain that travels over said sprockets, takeup idlers arranged at opposite sides of said chain, rockable carriers for said idlers, an arm combined With each of said carriers, a manually-operable adjusting shaft that passes freely through openings in the free end portions of said arms, a bearing on said rod, contractile springs connected to said bearing and to the upper end portions of said arms for causing said idlers to exert pressure on said chain in a direction tending to take up the slack in same, and stops on said rod arranged at the outer side of said arms for limiting the outward movement of the take-up idler which acts on the tight side of the chain. v i

REINHARD HILDEBRAND; 

